1. Technical Field
The present invention relates to a paper feeding device for feeding a sheet of printing paper to a printing position of a printing apparatus in order to print the paper, and a program for controlling the paper feeding device.
2. Related Art
In a paper feeding device for feeding a sheet of paper to a printing position of a printing apparatus in order to print the paper, it is known that the so-called skew (a slope of the paper) occurs in the transported paper due to the structure of the device. The paper feeding device disclosed in JP-A-2002-128286 (see paragraphs 0010 and 0034, FIG. 1, and so forth) includes a paper tray provided with a stationary edge guide and a movable edge guide for guiding the paper to be transported. The movable edge guide is integrally formed with a movable edge side hopper for pushing up the paper towards a paper feeding roller, and a movable edge side cam mechanism for driving the movable edge side hopper. With this configuration, if the movable edge guide is moved in line with a width of the paper, the movable edge side hopper and the movable edge side cam mechanism are also moved in line with the width of the paper. As a result, since the movable edge side hopper for pushing up the paper towards the paper feeding roller and the movable edge side cam mechanism move together in line with the width of the paper, the movable edge side hopper and the movable edge side cam mechanism are always structurally disposed at a position adjacent to each other, regardless of the paper size. Therefore, components for transmitting a driving force from the movable edge side cam mechanism to the movable edge side hopper are not twisted, and the movable edge side cam mechanism can properly drive the movable edge side hopper. Consequently, balance between the pushing-up of the paper by the movable edge side hopper driven in the movable edge side cam mechanism and the pushing-up of the paper by the stationary edge side hopper driven in a stationary edge side cam mechanism fixedly disposed is maintained, so that a transport load is not applied to one side of the paper by pushing up both ends thereof towards the paper feeding roller by the use of both hoppers, thereby preventing occurrence of failure such as skew.
Such a paper feeding device takes account of the skew of the paper which is caused by the structure of the device or the like. However, no regard is paid to the skew of the paper which is caused by a phenomenon which is unrelated to the structure of the device itself, for example, use environment of the printing apparatus, such as an installation place of the printing apparatus, after shipping of the device, a user's habit of adjusting the guide width of the edge guide, which is provided on the paper tray, voluntarily to feed the paper, or the like. Therefore, there is much room for improvement.